Load-hauling trailers or shipping containers for transporting bulk materials are typically backed up to a loading dock and loaded with the aid of a ram device. Bulk materials are typically at least somewhat compressible, and may include, for example, paper or paper products, garbage, recyclables, or construction waste. For efficiency reasons, it is desirable to provide a loading machine that includes a ram device for pushing bulk materials toward the closed end of the trailer, compressing the bulk materials in the process. However, some of the pressure exerted on the bulk materials typically causes the bulk materials to exert outward pressure on any trailer surface with which the materials are in direct contact, such as the floor, side walls, closed trailer end, and ceiling. To resist this outward pressure and prevent bowing of the sidewalls, such trailers may typically be equipped with sidewalls that are structurally stronger, and thus typically heavier, than would otherwise be necessary for transporting the bulk materials. Alternatively, such as for trailers not equipped with strengthened sidewalls, the ram pressure may be reduced to prevent damage to the trailer sidewalls, resulting in less bulk material being loaded into the trailer than would otherwise be possible.